Biologist Charles Darwin
called the mandrill the most vividly colored specimen in mammaldom. These
large monkeys have white eyelids, blue cheeks, red noses, yellow beards,
and lilac-colored rumps. Male mandrills are twice the size of females,
ranging between 50 and 90 pounds, and their colorful markings become much
brighter when they reach sexual maturity. Their size and their long canine
teeth make the adult male mandrill the most formidable of any monkey.

Mandrills are found in the
thick evergreen rainforests of central West Africa, from Cameroon to Gabon
and New Guinea. They prefer areas with a supply of drinking water and
little ground cover. Their home range is about 115 miles, the largest
known for any primate.

Until recently, it was thought
that mandrills belonged to the baboon family, and it was assumed that
mandrills had a social structure similar to other members of this family.
However, a recent DNA study showing that mandrills are neither baboons
nor closely related to them, combined with new field research on the mandrill,
has given us a very different picture of mandrill society.

Behaviorally, mandrills seem
to be unique. They travel in much larger groups than previously believed.
Scientists have counted groups containing up to 1,350 individuals, with
a mean group size of around 620. The members of these groups remain together
for years, forming a tight knit and stable society. Another surprise is
that these groups are comprised almost exclusively of females and their
young. Males of breeding age join the groups only during the breeding
season, which lasts from May until November. The rest of the year, the
males are solitary. When the females come into estrus, males from all
around descend on the group, battling fiercely with each other for breeding
privileges.

A single infant is born with
fur and with its eyes already open. Newborns cling to the mother's belly
immediately after birth. Infants have a black coat and pink skin for the
first two months. Family bonds are long-lasting; the mother-daughter bond
continues into adulthood, and the maternal bond with sons lasts until
sexual maturity.

Mandrills are omnivores that
browse on a wide range of foods, covering 3 to 5 miles a day in their
foraging along the forest floor. They will eat nuts, seeds, leaves, insects,
fruit, bark, grass, fungi, and small animals. Mandrills have cheek pouches
that can hold a substantial quantity of food, leaving their hands and
feet free for running and climbing. At night, mandrills sleep in trees.

Large groups of mandrills
are very noisy and emit a continuous chorus of two-phase barks, frequent
"crowing," grunts, and squeals. Females and young use a call to locate
each other and a call of alarm when they feel threatened. A mandrill's
coloring gets brighter when it becomes excited or angry. Male mandrills
present a threat by "yawning," thereby fully exposing their long canines.
A slight revealing of the teeth, possibly accompanied by teeth chattering,
communicates a greeting, general friendliness, and a sense of well-being.

The primary predator of the
mandrill is the leopard. The two biggest threats to this endangered species
are posed by bush meat hunters and habitat destruction. The slow reproductive
rate of mandrills puts their population at even greater risk.